Stockholders' Equity (Components of Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance			$ (772,182)	$ (53,935)
Net change in unrealized gain (loss)			(2,559)	(594,455)
Reclassification of net income or loss realized and included in earnings	$ 11,245	$ (5,570)	20,765	(9,408)
Valuation adjustments to employee benefit plans			(7,521)	(7,987)
Amortization of unrealized net loss on securities transferred to HTM	428	266	922	527
Income tax (expense) benefit	22,194	48,941	(2,211)	138,081
Ending Balance	(762,786)	(527,177)	(762,786)	(527,177)
Accumulated Other Comprehensive Loss Available for Sale Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance			(584,408)	11,037
Net change in unrealized gain (loss)			17,678	(547,636)
Reclassification of net income or loss realized and included in earnings				1,707
Transfer of net unrealized loss from AFS to HTM securities portfolio				15,405
Income tax (expense) benefit			(3,737)	119,739
Ending Balance	(570,467)	(399,748)	(570,467)	(399,748)
Held to Maturity Securities Transferred from AFS [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance			(10,734)	153
Transfer of net unrealized loss from AFS to HTM securities portfolio				(15,405)
Amortization of unrealized net loss on securities transferred to HTM			922	527
Income tax (expense) benefit			(207)	3,358
Ending Balance	(10,019)	(11,367)	(10,019)	(11,367)
Employee Benefit Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance			(97,952)	(80,946)
Reclassification of net income or loss realized and included in earnings			3,272	1,652
Valuation adjustments to employee benefit plans			(7,521)	(7,987)
Income tax (expense) benefit			956	1,430
Ending Balance	(101,245)	(85,851)	(101,245)	(85,851)
Gains and Losses on Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance			(79,093)	16,284
Net change in unrealized gain (loss)			(20,943)	(47,287)
Reclassification of net income or loss realized and included in earnings			17,493	(12,767)
Income tax (expense) benefit			777	13,554
Ending Balance	(81,766)	(30,216)	(81,766)	(30,216)
Equity Method Investment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance			5	(463)
Net change in unrealized gain (loss)			706	468
Ending Balance	$ 711	$ 5	$ 711	$ 5